Hopefully, you’ve remembered to pay your taxes or file for an extension today — because the IRS most certainly won’t.

You’ve got until 11:59:59 p.m. to file your taxes today or ask for an extension electronically, according to tax preparer websites. If your return was rejected, you have until April 20 to refile to avoid penalties. (This applies to any American who filed on time but was rejected — not just those who owe the government money, an IRS spokesman said Tuesday.)

Below, find other tax-related things for businesses to note in April and May for businesses, though we did include the April 15 and April 20 days for staffers’ benefit. This is by no means exhaustive of everything your business should do or every date it should know, and the list applies to the federal level only.

April

April 15: Date for some businesses to file their tax returns and pay up. Also, the date for most Americans (except those living or working abroad, according to Intuit) to file their taxes.

April 15: Date for corporations to deposit first part of estimated 2015 tax. Form 1120-W can help with these projections.

April 15: Pay nonpayroll withholding, withheld income tax, Medicare and Social Security for March if you’re on the monthly deposit rule.

April 20: Deadline for any American whose tax return was rejected but filed on time to refile and avoid a penalty.

April 30: File Form 941 (withheld income tax, Medicare and Social Security) for the first quarter of 2015 and pay up/deposit whatever’s left if you haven’t already. You have until May 11 to file this if you deposited in full and on time.

April 30: Pay federal unemployment tax through March.

May

May 11: File Form 941 (withheld income tax, Medicare and Social Security) for the first quarter of 2015 if you’ve already deposited everything on time.

May 15: Pay nonpayroll withholding, withheld income tax, Medicare and Social Security for April if you’re on the monthly deposit rule.